This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | -14 |
| 9 | 45 |
| 10 | -101 |
| 11 | 189 |
| 12 | -331 |
| 13 | 668 |
| 14 | -1932 |
| 15 | 7206 |
| 16 | -27779 |
| 17 | 101365 |
| 18 | -347439 |
| 19 | 1139851 |
| 20 | -3690766 |
| 21 | 12258863 |
| 22 | -43341845 |
| 23 | 166059261 |
| 24 | -682516519 |
| 25 | 2930522990 |
| 26 | -12823188092 |
| 27 | 56366526324 |
| 28 | -247898684759 |
| 29 | 1094571175769 |
| 30 | -4890163717903 |
| 31 | 22310147976797 |